1. Field of the Invention
This invention relates to liquid flow control means, and, in particular, to means for controlling the filling of a receptacle, such as a dishwasher tub.
2. Description of the Prior Art
In one conventional dishwasher structure, a tub is provided having a sump portion in which dishwashing liquid is collected for recirculation as by being sprayed against the dishes being washed in the apparatus. The quantity of dishwashing liquid is conventionally controlled by filling the tub to a preselected normal full level from a pressurized liquid source. One example of such an apparatus is shown in United States Letters Pat. No. 3,331,374 of Bruce E. Stewart et al, owned by the assignee hereof. In said patent, the liquid level and flow control includes a drain outlet and a return outlet, with a solenoid operated valve for selectively closing the drain outlet. A float is attached to the valve to open it as the result of a high liquid level condition in the tub, even though the solenoid is de-energized to prevent draining of the liquid from the tub.
A number of different control valves for use in controlling liquid level in different devices are known in the art. Illustratively, a safety cutoff device for fuel supply lines shown in William C. Coleman United States Letters Pat. No. 2,174,055 is used in connection with a delivery of liquid fuel to a gas burning appliance. The Coleman device utilizes a float operated linkage to close the liquid inlet valve under certain operating conditions.
In United States Letters Pat. No. 2,547,098, Carl A. Smith et al disclose an electromagnetic valve having manual means for actuating the valve in event of failure of electrical power.
Thomas B. Chace et al, in United States Letters Pat. No. 2,548,651, show a fluid control system for laundering apparatus, having means for controlling the temperature of the washing liquid, and utilizing float actuated means for controlling a drain valve. A cup-shaped member is provided which operates to cut off liquid delivery, and a weight controlled unit is provided to stop delivery notwithstanding continued operation of the cup-shaped member.
George B. Klaber, in United States Letters Pat. No. 2,937,014, shows a float valve for controlling liquid delivery in a fuel supply line.
John H. Spragins, in United States Letters Pat. No. 2,664,094, shows a level control for controlling the level of dishwasher liquid in a separate well communicating with the tub for providing steam into the washing compartment.
In United States Letters Pat. No. 3,610,271 of Wilbur W. Jarvis, owned by the assignee hereof, a variable liquid level control for use with liquid receiving devices, such as dishwashers and the like, is disclosed as being controlled by a float having a plurality of buoyant compartments, with means for varying the buoyancy of the float by selectively closing the compartments.